Volcanic impacts on grasslands - a review.
Volcanic eruptions have a wide range of effects on many of the Earth's grassland systems, such as in Africa, the Americas and Iceland. The effects are determined by the severity of the impact, vegetation height and the resilience of the impacted system. Biological soil crusts, often an important component of dryland grazing systems, are severely affected by thin deposition of volcanic ash, whereas taller vegetation with ample nutrient supplies is more tolerant to such disturbances. Redistribution of airborne unconsolidated volcanic materials (tephra, including volcanic ash) in the aftermath of eruptions is often quite harmful to ecosystem survival. The interaction between volcanic events and land-use practices such as grazing is detrimental. Alien plant species in volcanic areas can severely interfere with ecosystem recovery.